R: Finding skewness

skew {semTools} | R Documentation

## Finding skewness

### Description

Finding skewness (g_{1}) of an object

### Usage

    skew(object, population = FALSE)

### Arguments

`object` | A vector used to find a skewness
`population` | `TRUE` to compute the parameter formula. `FALSE` to compute the sample statistic formula.

### Details

The skewness computed is g_{1}. The parameter skewness γ_{2} formula is

γ_{2} = \frac{μ_{3}}{μ^{3/2}_{2}},

where μ_{i} denotes the i order central moment.

The excessive kurtosis formula for sample statistic g_{2} is

g_{2} = \frac{k_{3}}{k^{2}_{2}},

where k_{i} are the i order k-statistic.

The standard error of the skewness is

Var(\hat{g}_2) = \frac{6}{N}

where N is the sample size.

### Value

A value of a skewness with a test statistic if the population is specified as `FALSE`

### Author(s)

Sunthud Pornprasertmanit (psunthud@gmail.com)

### References

Weisstein, Eric W. (n.d.). Skewness. Retrived from MathWorld–A Wolfram Web Resource: http://mathworld.wolfram.com/Skewness.html

### See Also

- `kurtosis` Find the univariate excessive kurtosis of a variable

- `mardiaSkew` Find Mardia's multivariate skewness of a set of variables

- `mardiaKurtosis` Find the Mardia's multivariate kurtosis of a set of variables

### Examples

    skew(1:5)

[Package semTools version 0.5-0 Index]